This invention relates to a new compound possessing excellent herbicidal activity, a process for preparing same and a herbicide comprising the new compound.
Many diphenylether compounds have previously been examined to determine their effects in practical use as herbicides. In many cases, the presence or absence, degree, mode of action, selectivity and persistence of the herbicidal activities of these compounds differ with even a slight difference in chemical structure of these compounds such as type, number and position of substituents. Thus, it is extremely difficult to estimate the herbicidal activity of these compounds from their similarity in chemical structure.
It is a well-known fact that some diphenylether compounds possess excellent herbicidal activity. For example, 2,4-dichloro-4'-nitrodiphenyl ether (referred to hereinafter as NIP) and 2,4,6-trichloro-4'-nitrodiphenyl ether (referred to hereinafter as CNP) are widely used as herbicides in rice fields.
Ideal herbicides are required to exhibit on one hand a very strong herbicidal activity to undesirable plants even at a very low level concentration and on the other hand an extremely low phyto-toxicity to useful plants. However, known herbicides still fail to meet fully either or both of these requirements. In recent years, the problem of environmental pollution has been raised in connection with the use of agricultural chemicals and the use of a highly effective herbicide in an amount as small as possible is recommended to minimize any environmental effect. Under these circumstances, there is a great demand for a new type of herbicide which meets the aforementioned requirements.